This July 2007 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Piper Cherokee Six.
Location: Tyringham, Mass.
Injuries: 2 Fatal.
Aircraft damage: Destroyed.
What reportedly happened: The pilot obtained a preflight weather briefing and was advised of a SIGMET for thunderstorms. The pilot took off. When queried by air traffic control about the conditions at altitude, the pilot replied, “The ride has been good, mostly light chop. We’ve had some light precipitation, but nothing at the moment. We may be getting back into here, it’s getting a little darker.” The controller advised the pilot “extreme precipitations were off to the right side, about seven miles heading your way at 30 knots.”
A few minutes later, the controller then advised all aircraft that a convective SIGMET was in effect for the area. Seven minutes later, the pilot advised the controller that he was “getting into it pretty good over here,” and asked to divert to the south. The controller approved the diversion, and advised the pilot to contact him when he was back on course. The controller asked the pilot to report his flight conditions, and the pilot advised “severe.” The controller then asked the pilot if he was able to maintain altitude because his radar showed that he was descending. Radar contact and communications were lost a short time later. Investigators determined that the aircraft broke up in flight.
Review of air traffic control data revealed that a relief controller had been briefed to turn the accident airplane due to weather, however, the relief controller failed to issue weather information or initiate a flight deviation around known and clearly observed weather, despite a light workload at the time.
Probable cause: The pilot’s inadvertent encounter with thunderstorms during cruise flight. Contributing to the accident was the failure of air traffic control to appropriately issue weather information and initiate an in-flight deviation around known and clearly observed weather.
